This invention relates to a method for forming a wear-resistant coating on the surface of a metallic article, and more particularly, to a method of forming a wear-resistant coating on the surface of a machine part which may be used for a plastic forming machine.
Conventionally, the formation of a wear-resistant coating on an article has been carried out by methods of spray coating the article or laminating the article alternatively with a wear-resistant powder of metal and a slurry of ceramic and then sintering the article.
When the spray coating method is used, the coating comes off easily because the coating has a thickness of about 0.2 mm, which is too thin to withstand "Herz Stress" and is held on the machine part by a small adhering force.
When the laminating and sintering method is used, it is considerably difficult to form the coating uniformly because the powder of the metal permeates into the powder of the ceramic after sintering. Also, it takes a lot of time to machine a sintered workpiece because the surface of the sintered workpiece is rough because the organic binder reacts or melts at the boundary areas between the ceramic and the metal layers.